Question:

A 72-year-old man comes to the emergency department due to severe left lower leg pain that began as a tingling sensation several hours ago but has since become increasingly painful. Medical history is significant for hypertension, type 2 diabetes mellitus, paroxysmal atrial fibrillation, and osteoarthritis. The patient has a 45-pack-year smoking history. Blood pressure is 142/80 mm Hg, and pulse is 112/min and irregular. On physical examination, the left lower extremity skin appears mottled and is cool to the touch. The distal pulses of the left leg are not palpable. There is a right carotid bruit. Which of the following medications could have best prevented this patient’s acute condition?

Options:

A. Apixaban
B. Aspirin
C. Cilostazol
D. Clopidogrel
E. Diltiazem
F. Metoprolol

Answer: A. Apixaban

72-year-old male with severe left leg pain

(History: Hypertension, Type 2 Diabetes, Atrial Fibrillation)

⬇️

Irregular heart rhythm (Atrial Fibrillation (AF))
⬇️

Blood Stasis in Left Atrium

⬇️

Activation of coagulation cascade 

⬇️

⬇️

Formation of thrombus (clot)
⬇️

Thromboembolism

⬇️
🧠 Clot dislodges

⬇️

 Travels through systemic circulation
⬇️

Clot Occludes Peripheral Artery

⬇️

 Blocks arterial blood flow (e.g., femoral artery)
⬇️

↓ Blood supply

⬇️

Acute Limb Ischemia (ALI)

⬇️

Clinical Manifestations

Pain (↑ due to ischemia)

Pulselessness (no distal blood flow)

Pallor (mottled skin)

Paresthesia (tingling sensation)

Coolness (↓ perfusion)
⬇️

⬇️

Choice: Prevention with Anticoagulant (e.g., Apixaban)
🧠 Prevents clot formation by inhibiting thrombin/factor Xa
⬇️

Prevents formation of fibrin-based thrombus → Reduces risk of embolization from atrial fibrillation

⬇️

No Clot Formation → No Embolism → No Ischemia

Why Other Options Are Wrong?

B. Aspirin
🧠 Incorrect: Aspirin is an antiplatelet drug, not an anticoagulant. It primarily prevents arterial thrombosis due to atherosclerosis but is less effective in preventing embolic events in atrial fibrillation (AF), where anticoagulation is needed.

C. Cilostazol
🧠 Incorrect: Cilostazol is used for peripheral artery disease by improving blood flow via vasodilation and inhibiting platelet aggregation. It doesn't prevent thromboembolic events associated with AF, which is the key cause of this patient's ischemia.

D. Clopidogrel
🧠 Incorrect: Clopidogrel is also an antiplatelet agent. Like aspirin, it’s used to prevent atherosclerotic events, not cardioembolic events from atrial fibrillation, where anticoagulants are the standard preventive treatment.

E. Diltiazem
🧠 Incorrect: Diltiazem is a calcium channel blocker used for rate control in AF but does not prevent clot formation or embolization. It manages heart rate, not the underlying risk of thromboembolism.

F. Metoprolol
🧠 Incorrect: Metoprolol is a beta-blocker that controls heart rate in AF but doesn’t prevent the formation of thrombi. Rate control alone won’t prevent embolic complications; anticoagulation is required.

Flashcards

Stay Hungry, Stay Curious!

Your Brothers In This Struggle

Dr. Shoaib Ahmad